gistfile1.php

if($projects = $service->getProjects()){
//if($projects = $this->projectRepository->getAllProjectsByService($service)){
	foreach($projects as $project){
		foreach($project->getSlides() as $slide)
		$slidearray[] = $this->formatSlide($slide);
	}
}		

gistfile2.php

	/**
	 * getAllProjectsByService
	 *
	 * @param $service
	 * @return
	 */
	public function getAllProjectsByService($service) {
		$query = $this->createQuery();
		$query->getQuerySettings()->setRespectEnableFields(false);
		return $query->matching($query->contains('service',$service))->execute();
	}